1. Field of the Invention
The present invention relates to a substrate processing apparatus, a substrate annealing method, and a semiconductor device manufacturing method and, more particularly, to a substrate processing apparatus, substrate annealing method, and semiconductor device manufacturing method used in, for example, annealing a silicon carbide (SiC) substrate.
2. Description of the Related Art
A conventionally known substrate processing apparatus includes a heating plate, annular cooling unit, and substrate holder. The heating plate is set in the lower portion of a vacuum chamber. The cooling unit is set in the upper portion of the vacuum chamber. The substrate holder is made of a material with a high thermal conductivity and is inserted between the heating plate and the cooling unit to be liftable (see, e.g., Japanese Patent Laid-Open No. 2003-318076). The substrate processing apparatus anneals a substrate by lowering the substrate holder which mounts the substrate to bring the lower surface of the substrate holder into contact with the heating plate, and heating the substrate through the substrate holder. The substrate processing apparatus then cools the substrate through the substrate holder by lifting the substrate holder to bring the periphery of the substrate holder into contact with the cooling unit.
However, note that the above-mentioned conventional substrate processing apparatus, substrate annealing method, and semiconductor device manufacturing method heat the substrate through the substrate holder by heat transfer between them. For this reason, heating nonuniformity may occur unless the substrate is uniformly in contact with the substrate holder throughout the entire contact portion. When, for example, the substrate having undergone implantation and annealing is warped, and portions in which the substrate is in contact and not in contact with the substrate holder are often generated. This may deteriorate the in-plane uniformity of the annealing characteristic of the heated substrate. Note also that the substrate cools from the periphery of the substrate holder. For this reason, the substrate not only cannot uniformly cool the entire surface but also requires a long cooling time, that is, the conventional apparatus undesirably has low productivity to satisfactorily function as a substrate processing apparatus or semiconductor manufacturing apparatus.